MUMBAI: The accused in the Mumbai gangrape case have admitted to attacking at least fourwomen in Shakti Mills complex in the last six months, including raping a ragpicker and a sex worker besides molesting a girl when a couple entered the desolate area for privacy, police said.

The gang got emboldened as none of the earlier victims lodged any complaint and perhaps explains the brazenness with which they attacked the photojournalist and her male colleague when they went there on Thursday evening.

The accused had clicked the rape survivor’s photograph on their cell phones and threatened her not to go to police and slipped back to their normal lives. “They were confident that would get away with such blackmailing as in the past,” said a police officer.

Police have appealed to all the victims to come forward. “There are reports (of past attacks), but so far nobody has come forward to register a complaint. If somebody comes, we will surely file fresh complaints,” said Himanshu Roy, joint commissioner of police.

In another revelation, investigators learnt why the five, despite three of them having theft cases against them, did not take away either the phones or the expensive cameras of the photojournalist and her male colleague.

Qasim Shaikh and Chand Shaikh, both history-sheeters, had warned other gang members that stealing electronic goods, particularly cell phones, could lead to them being traced.

During interrogation, all five told the police that they had molested a girl after she came to the complex with her male companion. A few weeks later, they targeted a ragpicker and a month before Thursday’s attack, they brought a sex worker into the mill. They have admitted a fourth attack, but the details are unclear.

On Tuesday, the crime branch traced an accused’s friend who could be made a key witness. Salim Ansari, arrested from Delhi, and Vijay Jadhav had spotted the photojournalists entering the mill and immediately called up their friends. “Qasim Shaikh, Chand Shaikh and Siraj Khan were playing cards on the other side of the mill (away from the railway tracks through which the photojournalists entered) on Thursday. Now we have got a person who confirmed that Qasim received a call from Salim after which they left,” said an officer.

The crime branch is also questioning two ragpickers after the survivor’s male colleague told the police that one had passed by while the rape was on.

A team of the Central Forensic Science Laboratory (CFSL), Hyderabad, and Gujarat Forensic Science Laboratory visited the mill and collected scientific evidence. Officials said now they have advanced technology that enables them to retrieve pollen as evidence even days after a crime.

Sources said the Gujarat FSL team led by Dr S Acharya conducted psychological tests on the accused. “Voice-Layered Analysis (VLA) is a test in which we record the voice of an accused in normal condition and than ask him to talk in unusual circumstances which helps us understand whether he is telling the truth or not,” explained an FSL official. It is not admissible evidence, but helps investigation.

Bone and DNA tests were carried out on the accused to determine their ages and to match their semen with those on clothes. Police said identification parade of the accused will be held next week.

The National Woman commission led by Mamta Sharma is likely to arrive in Mumbai on August 29 to meet senior police officers and discuss progress of the probe.